The present invention relates generally to motors having shafts adapted to different sizes and, to adapters for motor shafts.
Numerous different manufacturers produce motors that are to be utilized for various applications, including ones where a pulley, blower wheel, or fan is directly attached to the motor shaft. In addition, numerous different manufacturers produce driven devices such as blower wheels, fans, and pulleys which usually are available. Frequently, a situation will arise where it would be most economical for a manufacturer to use a driven device from a first source (or from a pre-existing inventory) and a motor from another source (or from a pre-existing inventory). However, standards do not exist in the industry such that motors of the desired power rating size will invariably have a shaft diameter that will interfit with the bores of all blower wheels or fans which the motor would otherwise be capable of driving. This condition has long existed, and it has become common practice to sell shaft adapters which adapt an undersize motor shaft to driven devices with larger shaft bores.
More specifically, it is common to utilize an adapter which will slide onto a 7.94 mm diameter shaft (5/16 in.) and have a 9.52 mm (3/8 in.) outer diameter. Another common expansion involves the use of adapters to adapt a 12.7 mm (1/4 in.) diameter motor shaft to a 15.87 mm (5/8 in.) diameter driven device bore.
General Electric Company, the assignee of the present application (as well as the related applications identified hereinabove), for more than a year prior to the filing date of this application, has sold motors and shaft adapters of various configurations. For example, motors and shaft adapters have been marketed wherein the adapter usually has been produced on an automatic screw machine. Typically, these adapters are provided with windows, and a set screw or other fastening device is threaded through the driven device hub, passes through the window, and bears against the motor shaft. Because of the construction of this type of adapter, it is necessary to grind a flat on the motor shaft in order to accommodate any burrs which would be raised by the set screws, and this of course represents an added expense. In addition, if adapters are to be press fit onto the shaft of a motor, equipment and manpower must be expended. On the other hand, if such an adapter is manufactured so that it will easily slide on and off of the shaft, packaging and handling problems are encountered. For example, if loose fitting tubular sleeves are positioned on a motor shaft at time of shipment, the loose fitting sleeves may be easily separated from the motors, and subsequently have to be found and repositioned on the motor shaft. Moreover, when a blower wheel or fan is mounted on such a shaft adapter, time and extra care must be taken to insure that the shaft adapter is properly positioned, not only with respect to the motor shaft but also with respect to the hub of the fan or blower wheel.
In another approach that has been utilized more than a year prior to this application, adapters in the form of coil springs have been used. Typically, such a spring would have a length of about 31.75 mm (11/4 in.), an outer diameter of nominally 9.48 mm (0.373 in.), a nominal inner diameter of 7.95 mm (0.313 in.), and be made from tin plated music wire having a diameter of about 0.76 mm (0.03 in.). While the coil spring type of adapter may be fairly easily threaded onto and off a motor shaft, the expense associated with producing such an adapter is objectionable and the material from which such adapters are produced is also relatively expensive. In addition, spring adapters are not provided with windows through which set screws or other mounting hardware can pass to positively engage the motor shaft.
As another variation, split sleeve shaft adapters have long been used. These adapters are typically 31.75 mm long (11/4 in.) and made from steel or aluminum sheet material 0.78 mm (0.0307 in.) thick. The sheet material is rolled to form a split sleeve or cylinder having an internal diameter that can either be a slip or press fit on a shaft. This type of adapter most typically is used in applications where key ways are formed in the motor shaft, and keys form a positive interlock with a key way in the driven device.
The problems described herein exist in general for both original equipment manufacturers and replacement motor suppliers. For example, replacement motors generally can be stocked much more economically by a distributor, retailer, or service shop if the replacement motor is supplied with a relatively small shaft and one or more adapters which can be utilized to adapt the shaft to one or more preselected larger diameters. This approach provides much more flexibility in using a given motor for a number of different applications.
It should now be understood that it would be desirable to provide motors with adapted shafts wherein the adapters utilized would be sufficiently secured on the shaft to prevent inadvertent dislodgement during packing, handling, and shipping of the motor. On the other hand, it would be desirable that such adapters be readily and easily removable from the shaft without requiring the use of tools or undue amounts of force, and without damage either to the adapter or shaft. It would be particularly desirable to provide adapters that would have the desirable attributes just discussed which would be relatively inexpensive to manufacture, which would utilize inexpensive materials, and which would be manufactured by a process which would be straight-forward and simple in nature but not require the use of exotic materials, equipment, or manufacturing controls. In addition to all of the above, it would be most desirable to provide adapters (as well as methods of attaching the same to motor shafts, and methods of making the same) which could be easily and manually positioned on a shaft, not easily be removed from the shaft inadvertently, which would be positively located on the shaft, and also accommodate a burr raised by a set screw. Among other things, this would eliminate the need to undergo the extra expense associated with grinding a flat on a shaft for the purpose of accommodating a burr raised by set screws or the like. I have now also found that low vibration transmission from a motor to a mounting structure may be related to the fit of a blower hub on a shaft/shaft adapter. Thus, it would also be desirable to provide shaft adapters that would make a minimum contribution to vibration transmissions because of the fit between the shaft and shaft adapter and driven device.
Accordingly, it is a general object of the present invention to provide new and improved motors having adapted shafts, shaft adapters.
It is a more particular object of the present invention to provide a new and improved motor shaft adapter which may be easily positioned by hand on a motor shaft and precisely located on the motor shaft and yet not be easily, inadvertently separated from the motor shaft even though the adapter may be readily removed from the shaft manually.
It is a more specific object of the present invention to provide a new and improved motor shaft adapter that may be easily mounted on a motor shaft manually and yet which will positively interlock with the shaft to insure retention of the adapter on the shaft.
It is a further object of the present invention to provide new and improved shaft adapters whereby commonly available sheet material may be stamped and formed into a configuration that will permit the attainment of the above-mentioned objects.
Yet another object of the present invention is to provide a new and improved shaft adapter that may be manually slipped on a motor shaft and yet be easily removed therefrom, and yet which will accommodate a burr on the shaft without requiring a flat on the shaft.
Still another object of the present invention is to provide a new and improved shaft adapter which can be easily positioned on a shaft, which will establish a positive interlock with the shaft, which can be easily, manually removed from the shaft, and which will represent a minimum contribution to vibration transmission when the motor with the shaft adapter is utilized to drive air moving equipment such as a blower.